1. Field of the Invention
This invention is related to wafer bonding for optoelectronic applications. More particularly, the invention relates to wafer bonding (Al, In, Ga)N and Zn(S, Se) for optoelectronic applications.
2. Description of the Related Art
(Note: This application references a number of different publications as indicated throughout the specification by one or more reference numbers within brackets, e.g., [x]. A list of these different publications ordered according to these reference numbers can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.) Wafer bonding technology using a different combination of materials such as InP/GaAs, (AlxGa1-x)0.5In0.5P/GaP, InP/GaN, GaAs/GaN have been studied for applications of optoelectronic integration, light-emitting diodes (LEDs), vertical cavity surface emitting lasers (VCSELs) and electronic devices. [1,2,3,4].
In the nitride material system, there are several challenges in fabricating distributed Bragg reflector (DBR) structures. The general approach is to epitaxially grow a structure made up of alternating quarter-wavelength GaN and AlGaN layers. Because of the 2.5% lattice mismatch between GaN and AlN, the AlN content of the ternary material has to kept low in order to avoid cracks in the layers, which causes a large number of mirror pairs in order to reach a high reflectivity, and the width of the reflectivity stop-band is quite narrow. [5].
Another approach is the method of using an AlInN/GaN combination to avoid the generation of cracks. [6]. But, these approaches continue to have difficulty in fabricating conductive DBRs, especially a conductive p-type DBR structure.
What is needed, however, are improved methods of wafer bonding for optoelectronic applications. The present invention satisfies this need.